1. Field of Invention
The techniques described herein relate generally to Chemical Mechanical Polishing (CMP), and more particularly to techniques for planarizing a semiconductor wafer having overlapping layers.
2. Discussion of the Related Art
Chemical Mechanical Polishing (CMP) is a technique commonly used for polishing semiconductor wafers to obtain a substantially planar surface. Achieving a planar surface can be important to achieve uniformity and high yield, and obtain suitable depth of focus for subsequent photolithographic alignment steps. Conventional CMP techniques use a polishing pad that polishes the semiconductor wafer using an abrasive slurry and chemical mixture.